1. Field of the Invention
This invention relates to solutions of electrically conductive substituted or unsubstituted polyanilines and to methods of forming such solutions. Another aspect of this invention relates to a method of using such solutions to form conducting polymer articles, including films, and methods of using such solutions as electrically conducting solutions.
2. Prior Art
There has recently been an increased interest in the electrochemistry and electrical phenomena of polymeric systems. Recently, work has intensified with backbone polymers having extended conjugation in at least one backbone chain.
One conjugated polymer system currently under study is polyaniline. Kobayashi, Tetsuhiko, et al., J. Electroanal. Chem., "Electrochemical Reactions Concerned With Electrochromism of Polyaniline Film-Coated Electrodes", 177 (1984) 281-291, describes various experiments in which spectro electro-chemical measurement of a polyaniline film coated electrode were made. French Patent No. 1,519,729; French Patent of Addition 94,536; U.K. Patent 1,216,549; "Direct Current Conductivity of Polyaniline Sulfate", M. Donomedoff, F. Kautier - Cristojini, R. ReSur-vall, M. Jozefowicz, L-T. Yu, and R. Buvet, J. Chim. Phys. Physicohim. Brol 68, 1055 (1971); "Continuous Current Conductivity of Macromolecular Materials", L-T. Yu, M. Jozefowicz, and R. Buvet, Chim. Macromol. 1, 469 (1970); "Polyaniline Based Filmogenic Organic Conductive Polymers", D. LaBarre and M. Jozefowicz, C. R. Read. Sci., Ser. C, 269, 964 (1969); "Recently Discovered Properties of Semiconducting Polymers", M. Jozefowicz, L-T. Yu, J. Perichon, and R. Buvet, J. Polym. Sci., Part C, 22, 1187 (1967); "Electrochemical Properties of Polyaniline Sulfates", F. Cristojini, R. De Surville, and M. Jozefowicz, Cr. Read. Sci., Ser. C, 268, 1346 (1979); "Electrochemical Cells Using Protolytic Organic Semiconductors", R. De Surville, M. Jozefowicz, L-T. Yu, J. Perichon, R. Buvet, Electrochem. Ditn. 13, 1451 (1968); "Oligomers and Polymers Produced by Oxidation of Aromatic Amines", R. De Surville, M. Jozefowicz, and R. Buvet, Ann. Chem. (Paris), 2 5 (1967); "Experimental Study of the Direct Current Conductivity of Macromolecular Compounds" L-T. Yu, M. Borredon, M. Jozefowicz, G. Belorgey, and R. Buvet, J. Polym. Sci. Polym. Symp., 16, 2931 (1967); "Conductivity and Chemical Properties of Oligomeric Polyaniline", M. Jozefowicz, L-T. Yu, G. Belorgey, and R. Buvet, J. Polym. Sci., Polym. Symp., 16, 2934 (1967); "Products of the Catalytic Oxidation of Aromatic Amines", R. De Surville, M. Jozefowicz, and R. Buvet, Amm. Chem. (Paris), 2, 149 (1967); "Conductivity and Chemical Composition of Macromolecular Semiconductors", Rev. Gen. Electr., 75 1014 (1966); "Relation Between the Chemical and Electrochemical Properties of Macromolecular Semiconductors", M. Jozefowicz and L-T. Yu, Rev. Gen. Electr., 75 1008 (1966); "Preparation, Chemical Properties, and Electrical Conductivity of Poly-N-Alkyl Anilines in the Solid State", D. Muller and M. Jozefowicz, Bull. Soc. Chem. Fr. 4087 (1972).
U.S. Pat. Nos. 3,963,498 and 4,025,463 describe oligomeric polyanilines and substituted polyanilines having not more than 8 aniline repeat units which are described as being soluble in certain organic solvents and which are described as being useful in the formation of semi-conductors compositions. European Patent No. 0017717 is an apparent improvement in the compositions of U.S. Pat. Nos. 3,963,498 and 4,025,463 and states that the polyaniline can be formed into a latex composite through use of acetone solutions of the oligomers of polyaniline and a suitable binder polymer.
In the general field of conducting polyaniline, it was heretofore believed impossible to dope a high molecular weight polyaniline to the extent that it becomes a semi-conductor or conductor and thereafter dissolve or plasticize the doped, conductive form of polyaniline in common organic solvents. As used herein, a "plasticized composition" is a solid polymer which includes solvent molecules to an extent sufficient to render the article flexible (softened) and not brittle. The liquid additive is known as a plasticizer. The nature of plasticized materials is described in more detail in "Contemporary Polymer Chemistry," Harry R. Allcock and Frederick W. Lampe, Prentice-Hall, Inc. Englewood Cliffs, N.J., p. 13 (1981). In the absence of solutions or plasticized forms, the ability to form certain articles out of conductive polyaniline, and especially homogeneous conducting or semi-conducting polyaniline films, is restricted. Thus, a need exists for techniques to facilitate the fabrication of shaped conductive polyaniline articles, especially articles such as films, fibers and coatings.